The effect of cohesion coffecient in structural style Mangharak fault zone with use analuge modeling method

Category Tectonic & Seismotectonic
Group GSI.IR
Location The 24 Symposium of Geosciences
Holding Date 26 August 2007


The N-S strike-slip Mangharak fault zone is located in Zagros simply folded belt, and continuous from about Shiraz to south of Dehram for about 140 km. Various large salt plugs such as Jahani, Firuzabad, Gach in the middle part of Mangarak fault zone, and small salt plug in Kaylag thrust pierce the cover layers. Existence of salt plugs in this area indicates presence of basal decollement viscous layers at depth. Which may cause variation in structural style above and below the decollement. Spatial distribution of decollement layers are analyzed through experimental analogue modeling method. Results indicate that the higher cohesion coefficient between basement rock and cover sedimentary sequence, the lower is width of deformed zone and the tapper angle higher is of the thrust and fold belt. Existence of Hormoz salt complex has decreased the cohesion coefficient between basement and cover sequence. As a result, in the studied area the tapper angle of deformed belt is variable and is closely related to the distribution of the decollement layers. In the West of Mangharak fault zone, cohesion coefficient and tapper angle are high, width of deformed zone is low but in the East of Mangharak fault zone, cohesion coefficient and tapper angle are low, width of deformed zone is high